How to reduce repetition of textures
From your screenshot you have your Vector input of the texture set to Default - this will be using a UV Map to orient the textures on your faces. In order to maps your texture over the whole mesh you either need to change the UV map (search for online tutorials for UV Unwrapping - it can be quite a simple or complicated process, depending on your needs and situation) or switch to a Vector setting that does not use your UV map - such as Generated.

I your case, Generated would seem to be the best option since you want the texture projected over the whole mesh from above - so change Vector to Generated. However, I also note from your screenshot that you have your Mapping set to 'Normal' - this can produce unexpected results (I presume this was the result of you trying to adjust your mapping) - so change it to Texture. You should then adjust the Scale and Rotation to orient the image on the mesh how you desire.